1. Field of the Invention
The invention relates to monitoring systems and, more particularly, to systems which (1) can monitor the activities of persons with dementia, small children, or any other persons who are incapacitated and/or whose activities must be monitored on a more or less continuous basis and which (2) can help a caregiver monitor a person's presence in a bed, room, home and/or other indoor or outdoor area.
2. Discussion of the Related Art
As the population ages, there have been an increasing number of people who have dementia, disorientation or who require home care. Nursing homes and institutions have the capacity to handle only a small percentage of the people requiring care. The escalating costs of health care combined with the desire of most people to remain at home has put many people in the caregiving situation. The caregiver must constantly watch the person being cared for and is subject to severe psychological stress, physical deterioration, burnout and even premature death. There is a need to help these caregivers monitor their charges to enable them to reduce stress levels, enjoy a good night's sleep and have more peace of mind knowing that the monitored person is in a safe environment.
In addition, hospitals, subacute care centers, nursing homes, hospices and other healthcare institutions are charged with caring for the elderly with dementia or people of any age who are disoriented. Many of these patients attempt to leave a bed without realizing their condition or the potential for injury. Bed falls are a major concern to healthcare staff, and the escalating costs of injury, falls and monitoring time add significantly to an institution's cost and staff stress.
Bed falls can be prevented only by strapping the patients in their beds or otherwise rendering egress impossible. Such techniques are generally not readily adaptable for use with patients of radically different sizes and weight, are at best uncomfortable for the patient, and at worst are demeaning and may result in patient injury. There is thus a need for healthcare institutions to improve the safety of their facility, reduce the costs associated with bed falls, and reduce staff stress while at the same time maintaining patient comfort and dignity. There is also a major need to be able to monitor patients of all sizes and weights, to provide immediate detection and alarm in the event of bed fall or attempted egress, and to reduce the number of nuisance alarms.
Various devices have been proposed to monitor a person's presence in bed. Such devices typically employ a weight sensor which disables an alarm signal when compressed and spring back to their original position to permit the generation of an alarm when the person's weight is removed from the sensor. These devices exhibit several drawbacks and disadvantages. First, they are unacceptable for use with frail or young persons weighing less than 100 pounds because such patients are not sufficiently heavy to compress the sensing device and thus cannot disable the alarm signal. They also may be unacceptable for extremely heavy persons because such persons may permanently compress the sensor, thus preventing an alarm signal from being generated when the person leaves the bed. Such devices are also notoriously unreliable, produce a high number of false or "nuisance" alarms, and must be frequently repaired. These devices also often fail without alarming. Finally, such devices are incapable of generating an alarm signal until the patient has actually left the bed, thus preventing the caregiver from being alerted of an attempted egress. A need has therefore arisen to provide a monitoring device usable in a bed or another location in which the monitored person is relatively stationary for extended periods of time.
Monitoring is also required for small children or persons with dementia who still retain significant mobility. One such monitoring system, disclosed in U.S. Pat. No. 4,814,751 to Hawkins et al., monitors the strength of a signal emitted by a transmitter worn by the user and generates an alarm when this signal drops below a threshold strength, indicating that the user has left a "safe" area. The effectiveness of this and other, similar devices is typically limited by the fact that the range of such devices is fixed and thus cannot be adapted to different conditions, e.g., from use within a home to use in a larger area such as a yard or picnic area. Such devices are also prone to nuisance alarms because they cannot differentiate between a true alarm condition and a condition in which the person being monitored leaves the monitored area for only a very short time or in which the signal is blocked or interfered with for a short time. Even those systems which are capable of reducing the number of nuisance alarms are not adjustable for a particular caregiver's preference. In addition, no known systems of this type are capable of also operating as a bed monitoring system, thus requiring the caregiver to purchase separate systems for monitoring an area while the patient is still ambulatory and for subsequent monitoring a bed of the monitored person's condition deteriorates.